Dyeing of textile materials



April 21, 1970 J. L. SWINDALL DYEING OF TEXTILE MATERIALS Filed Sept. 25, 1968 United States Patent 3,507,423 DYEING OF TEXTILE MATERIALS John L. Swindall, Leicester, England, assignor to Samuel Pegg & Son Limited, Leicester, England, a British company Filed Sept. 23, 1968, Ser. No. 761,509 Claims priority, application Great Britain, Sept. 26, 1967, 43,702/ 67 Int. Cl. D06c /00 US. Cl. 223-76 6 Claims ABSTRACT OF THE DISCLOSURE The dye liquor used in a recirculation dyeboarding system is recovered by flushing it out of the dyeing vessel with steam used for boarding the goods, has the excess water acquired from the steam flashed off by evaporation, is made up to compensate for loss of dye absorbed by the dyed goods, and is wholly returned to the dyeing vessel for re-use.

This invention relates to the so-called dyeboarding of garments. In this technique the garments, usually stockings, are mounted on forms, and successive sets of formmounted garments are introduced into a closed chamber where they are subjected to a treatment including a dyeing phase in which they are showered or sprayed with dye liquor, and a setting phase, before, during, and/or after the dyeing phase, in which they are exposed to steam to set them to shape.

In a version of dyeboarding practice, the dyeing phase is performed on each successive set of garments in the closed chamber by a re-circulatory method in which a batch of dye liquor is introduced into the chamber, is showered or sprayed over the garments, is collected at the bottom of the chamber, is re-sprayed or re-showered on the garments, is collected again, and so on, in a continuous operation for a timed period. It is with this version of dyeboarding, hereinafter termed a dyeboarding process of the kind set forth, that the present invention is more particularly concerned.

As this process of the kind set forth is normally practised, at the end of the dyeing treatment of each set of garments the used batch of dye liquor is thrown away, and the next set dyed with a fresh batch. This rejection of dye liquor represents a definite economic loss in the process, especially as the liquor usually still retains some expensive chemical constituents, in the form of antifoam agents, dispersing agents and emulsifiers.

Methods of recovering the used dye liquor have been suggested but, as far as the present applicants are aware, these have not proven economically viable or have involved undue complexity in control apparatus.

It is an object of this invention to devise a dyeboarding process of the kind set forth which enables all the dye liquor to be recovered and used again, at least until it is completely degraded by contaminants in the goods treated, and this without undue elaboration in equipment or loss of time in the main dyeboarding activity.

To this end the present invention presents a dyeboarding process of the kind set forth in which the whole of the remainder of each batch of dye liquor unabsorbed by the dyed garments is returned, at the end of the dyeing phase, under steam impulsion to a dye recovery apparatus including a supply vessel, is treated to evaporate ofi? excess water represented by condensed steam in the returned liquor, and is sent back to the closed treatment chamber in the next dyeing phase.

This represents a very convenient method of recovering all the used dye liquor, especially where the steam flushing this liquor from the closed chamber is at the same time used to apply a setting or postbearing treatment to the dyed garments in the chamber.

These garments will, of course, have taken up some dye from the treating batch of liquor, wherefor the returned liquor can be made up whilst the water-removal is taking place.

It will also be appreciated that the dye recovery apparatus can be made from the main dyeboarding system, so that the dye recovery and make-up can be carried on without in any way impeding the continuance of the processing, e.g. drying, of the dyed garments and their replacement by fresh garments.

In an advantageous form of apparatus for performing the dye-recovery process of this invention the supply source referred to is provided by a main feed tank which is connected to a secondary tank or broiler in which excess water is evaporated or flashed off during each phase of the dye recovery. The thus-enriched or reconcentrated used dye liquor is returned from the secondary tank to the main feed tank or to the recirculatory system at the treatment vessel.

The invention will now be described with reference to the accompanying diagrammatic drawing.

In this drawing it is assumed that the treating vessel for use in a dyeboarding process consists of a fixed dished base 1 with a bell 2 which can be lowered and raised (by means not shown). When closed it defines a chamber 3 in which the dyeing and boarding phases are to take place. Upstanding from the base 1 is a perforated pipe 4 which is connected through a line 5 to a steam source. This serves for applying steam to goods in chamber 3. Also upstanding from base 2 is a riser pipe 6 supporting and leading to a perforated head 7 for showering dye onto garments in chamber 3. Pipe 6 is connected to the delivery side of a pump 8, the suction side of which is connected through a line 9 with a drain orifice in base 1.

The garments in this case are assumed to be stockings which are mounted on a set of forms 10 on carriage 11 which can be run into position beneath shower head 7 when the hell 2 is raised.

In the dyeing phase of a dyeboarding operation using the plant so far described, dyeing liquor is forwarded by pump 8 to the shower head 7, is sprinkled or showered over the stockings at 10 and returned to the pump via the drain orifice and line 9, to be circulated again in the same way. The batch of dye liquor for this purpose is obtained from a main feed tank 12 which is connected to the recirculation system 6, 7, 8, 9 through a line 13 feeding from an outlet of the bottom of tank 12. The parts of a dyeboarding, so far described, are not in themselves novel and are to be found in our prior Patent No. 3,181,- 749. They are here shown, however, as an example of dyeboarding process to which the present invention can be applied, and we will now describe a dye recovery apparatus in accordance with the invention as it is applied to this dyeboarding system.

This dye recovery apparatus comprises the use of a secondary tank or boiler 14 which can be gravity fed through a pipe 15 from the bottom of main feed tank 12. Secondary tank 14 has a cover 16 with a vent outlet 17 and with a heater coil 18 connected through line 19 to line 5 and hence to the steam source.

The main tank 12 also contains a steam heater coil 20. This can be alternatively connected to the steam source or to a cold water source, depending on whether cooling or heating of the tank 12 is required in any particular circumstances.

The tank 12 also has a cover 21, through which pass the discharge outlets from a container 22, for mixing and delivering metered quantities of dye liquor, and a cold water conduit 23.

Also projecting into tank 12 are two probes 24 and 25 respectively to detect lower and upper levels respectively of liquor in tank 12. When liquor falls below the tip of probe 24 the elfect is to close a valve 26 in line 15 between tanks 12 and 14 and to open valves 27 respectively in the water conduit 23 and in the outlet from container 22, where these have previously been prepared for operation (see below).

When liquor in tank 12 contacts the tip of probe 25 the elfect is to cause valves 27 and 28 to be closed.

In addition there are control valves and probes in this dye recovery apparatus which will be referred to in the subsequent description of the use of the arrangement illustrated as follows:

At the stage of recirculatory dyeing of stockings in the main treatment chamber 3 the dye recovery apparatus of this invention is isolated from the dyeboarding system. When the dyeing operation is terminated and pump 8 stopped a valve 29 in a line 30 from the bottom of pump 8, i.e. the lower point of the recirculatory system in discharging into tank 12, is opened by the controls of the main dyeboarding process. Steam is now injected against the work through pipe 4 to postboard the dyed stockings and simultaneously to flush out the used batch of the recirculated dye from chamber 3 through line 9 and line 30 to the main feed tank 12. During this stage of transfer of the used dye liquor the tank 12, all the valves in the dye recovery apparatus are closed with the exception of valve 29.

In will be observed that a probe 31 is provided in line 30 in the vicinity of valve 29 and this is arranged to detect the passage of liquor through the line and to react, when no further liquor passes, to close valve 29 and open valve 26 in line 15. It also sets valves 27 and 28 for operation in response to the activation of probes 24 and 25. As a consequence of the opening of valve 26 liquor drains from tank 12 into secondary tank 14 where the water is immediately flashed off by the heating coil 18.

The draining of liquor in this way causes the level in tank 12 to fall until the tip of probe 24 in tank 12 is exposed. When this occurs valve 26 is closed and valve 27 in the water conduit 23 opened. This admits cold water into tank 12 to cool the hot liquor therein and to condense the steam. The exposure of probe 24 also opens valve 28 to allow a preset quantity of concentrated dye to be discharged from container 22 into tank 12.

With the admission of water and, albeit only to a minor extent, of the concentrated dye liquor from 22, the level of liquor in tank 12 rises again until it reaches the tip of probe 25. This closes valves 27 and 28 to interrupt further water and dye feed into the tank and all parts of the dye recovery apparatus are thus once again isolated from the main dyeboarding system. They remain in this condition whilst the garments are being further treated, e.g. dried, and while the carriage 11 with the set of forms is removed from the chamber 3, a carriage of fresh stockings inserted, the bell 2 closed down again, and the next dyeing cycle commenced, e.g. after a preliminary boarding operation. At the commencement of this new dyeing phase, the timing controls of the system open a valve 32 in line 13, thus allowing the contents of tank 12 to be discharged into the system as the returned batch of dye liquor. At the same time the timing controls open valve 33 in a line 34 connecting the bottom of secondary tank 14 to line 13, wherefor the concentrated dye liquid from tank 14 is also returned to the dyeing cycle. Thereafter the valves 33 and 32 are closed and the dye recovery apparatus remains inoperative until the end of the dyeing when it is used in accordance with the foregoing description.

As a result all unabsorbed dye is recovered and used again in the process, until it becomes too degraded, when the total volume of the then available used dye liquor will be drained entirely from the system.

What I claim is:

1. In a dyeboarding process in which garments are subjected, in a closed treatment chamber, to setting by steam and to a dyeing phase by means of a single batch of dye liquor, which is recirculated in a closed circuit through the garments and a recycling agency, the improvement in which the remainder of the batch of dye liquir unabsorbed by the dyed garments is passed at the end of the dyeing phase, by steam impulsion to a dye recovery appratus including a supply vessel, is treated to evaporate ofi excess water represented by condensed steam in the returned liquor, and is sent back to the closed treatment chamber in the next dyeing phase.

2. A dyeboarding process according to claim 1, in which a portion of the returned batch of dye liquor is run off into a secondary vessel and subject to flash evaporation, and the residue of this evaporation is sent back to the closed treatment chamber with the next batch of dye liquor.

3. A dyeboarding process according to claim 1 in which the returned batch of dye liquor is made up with fresh liquor in the supply vessel to compensate for dye taken up by the dyed garments.

4. A dye boarding process according to claim 1 in which the dye liquor is returned to the supply vessel by steam which is used to apply a postboarding treatment to dyed garments in the closed chamber.

5. A dye recovery apparatus for carrying of the process claimed in claim 1, comprising a supply vessel in the form of a main feed tank connected to the circulatory sprayor shower-dyeing system of a main dyeboarding plant, and a secondary tank or boiler communicating with said main feed tank and incorporating heating means for evaporating water from dye liquor delivered thereto from the main feed tank.

6. A dye recovery apparatus according to claim 5, in which there is a valve-controlled gravity flow connection between the main feed tank and the secondary tank, and a first level detector device is provided in the main feed tank to close this valve when the level of liquid in this tank is below a predetermined level and to open means for the admission of make-up dye liquor into said main feed tank, and a second level detector is provided in the latter to interrupt this admission when the level in the main feed tank reaches a predetermined maximum.

References Cited UNITED STATES PATENTS 3,125,248 3/ 1964 Brewin 22376 X 3,181,749 5/ 196-5 Helliwell et a1. 22376 3,417,414 12/1968 Claiborne 8158 MERVIN STEIN, Primary Examiner G. V. LARKIN, Assistant Examiner US. Cl. X.R. 8149.1, 158 

